Retired Army lieutenant colonel Robert A. Owendoff, 65, a veteran of World War II and the Korean conflict and a recognized authority on solar navigational systems, died of a cerebral hemorrhage Friday at Commonwealth Doctors Hospital in Fairfax.

An engineer, he served on active duty in the old Chemical Warfare Service in Europe during World War II and in Korea during the conflict there. He retired from the Army Reserve in 1964.

Lt. Col. Owendoff and a son, Navy Lt. Cmdr. Robert S. Owendoff, developed several innovative techniques in the field of solar navigational systems and coauthored a book which set forth their ideas, "Better Ways of Pathfinding," in 1964. They also collaborated in articles in this field for such publications as the National Geographic and the Journal of the Institute of Navigation.

Since the mid-1950s, Col. Owendoff worked locally as an engineer for several firms, including the Gilbane Building Co. of Rhode Island and the General Electric Co. He was a civil engineer for the Capital Mortgage Investments company in Chevy Chase for about six years before retiring in 1977.

Col. Owendoff was born in Brooklyn, N.Y., and earned a bachelor's degree in chemical engineering from The Cooper Union for the Advancement of Science and Art in New York City. He also earned master's degrees in business administration from New York University and Maastricht University in the Netherlands.

He was a longtime resident of Fairfax County, a member of the West Virginia Society of Surveyors and the founder of a local chapter of the society.

Besides his son, Robert, of Newport, R.I., survivors include his wife, Vauda M., of Fairfax; another son, Air Force Capt. James M., of Oxon Hill; a brother, Harold, of Lincroft, N.J., and two grandsons.